Empty comments

[Dahaka934]

Why do you use a final private static default comment?

final private static ConfigOrigin defaultValueOrigin = SimpleConfigOrigin
            .newSimple("hardcoded value");

Maybe you add possibility to set default comment in ConfigRenderOptions, for example?

Also, if I use ConfigValueFactory.fromAnyRef(obj, "") then generated empty comment with '#'.

#
value=1

Maybe in the case of empty lines do not need to generate a comment?

[havocp]

Skipping empty descriptions seems OK. Could allow null to be passed to fromAnyRef maybe and then skip null descriptions instead, might be cleaner, I think treating empty string as unset often ends in tears.

Implementation-wise I guess SimpleConfigOrigin would need the notion of an unset description and then at render time it could be skipped. I probably wouldn't make the ConfigOrigin.description getter return null (the docs state that it never will), instead I might make it able to have null internally, and return "hardcoded value" if it's null, and have a separate getter the render method can use like descriptionIsDefault() or something, to see if really it was unset.

For changing the default, the additional API and docs needed in ConfigRenderOptions for that feels a bit heavy to me. I think it might be hard to write the docs in a way that makes much sense. ("The description to render in a comment above values which were created in code rather than parsed from a file" ? seems a bit obscure, I feel like next to no one would use it...)

Note that if the format of the output matters to you much, the right direction is probably to be using and enhancing the ConfigDocument API (see #280 for history, #300 for one of the larger next steps). The Config object is meant to represent the actual runtime configuration, not a parse tree, so it does not preserve formatting or anything like that. The render method is really intended for debug output, not saving files, and the comments are only there to help with that. So I don't want to go overboard adding ways to fine-tune the render output. But easy fixes that don't add much API, sure.

[Dahaka934]

Thanks for the detailed answer.
Could you fix at least the empty comments # ?
So that we can control the generation of comments when generating config.

[havocp]

I don't have immediate plans to make this PR but if someone did I would try allowing a null originDescription when creating a new origin here:

config/config/src/main/java/com/typesafe/config/impl/ConfigImpl.java

Lines 185 to 190 in e1c2640

	private static ConfigOrigin valueOrigin(String originDescription) {
	if (originDescription == null)
	return defaultValueOrigin;
	else
	return SimpleConfigOrigin.newSimple(originDescription);
	}

So allow a null originDescription to be passed in.

And have tests for the null-passed-in-to-ConfigValueFactory.fromAnyRef case, for sure.

Then rename SimpleConfigOrigin.description field to descriptionOrNull

config/config/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java

Line 38 in e1c2640

this.description = description;

In here if descriptionOrNull is null, default description to "hardcoded value"

config/config/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java

Line 132 in e1c2640

public String description() {

Add a method to ConfigOrigin descriptionSetwhich returns descriptionOrNull != null and then in the render code, if the description is not set, skip the comment.

Not sure that will work out but that' what I'd try.

[Dahaka934]

Why not just skip comment rendering if description().isEmpty()? And no need to add additional features.

[Dahaka934]

There are two places with next code:

config/config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java

Lines 488 to 498 in ea45ea3

	if (options.getOriginComments()) {
	String[] lines = v.origin().description().split("\n");
	for (String l : lines) {
	indent(sb, indent + 1, options);
	sb.append('#');
	if (!l.isEmpty())
	sb.append(' ');
	sb.append(l);
	sb.append("\n");
	}
	}

Maybe, replace it to something like this?

if (options.getOriginComments()) {
    String desc = v.origin().description();
    if (!desc.isEmpty()) {
        String[] lines = desc.split("\n");
        for (String l : lines) {
            indent(sb, indent + 1, options);
            sb.append('#');
            if (!l.isEmpty())
                sb.append(' ');
            sb.append(l);
            sb.append("\n");
        }
    }
}